ietf-dkim
[Top] [All Lists]

Re: DKIM TTPs (was Re: [ietf-dkim] editorials and nits)

2006-07-05 18:23:08

On Jul 5, 2006, at 4:41 PM, Stephen Farrell wrote:

Douglas Otis wrote:
On Jul 5, 2006, at 2:36 PM, Paul Hoffman wrote:
At 12:44 PM -0700 7/5/06, Douglas Otis wrote:
DKIM generally represents a domain wide entity. A trusted third party (TTP) establishes trust between two parties when both trust the third party. For DKIM, the TTP would be the signing domain verified by DNS.

This is completely wrong, and goes against nearly everything that this WG has been working on. The signing domain is *not* trusted.

Does anyone other than Doug think that it is?
You have misunderstood what was being said.

Clash of terms there. The DNS, as used by DKIM, is a TTP in
crypto-protocol terms according to the well-understood use of that
term [1]. I think I first heard such a definition 20 years ago.

From your reference:
---
In cryptography, a trusted third party (TTP) is an entity which facilitates interactions between two parties who both trust the third party; they use this trust to secure their own interactions. TTPs are common in cryptographic protocols, for example, a certificate authority (CA).
---

While DNS associates a key with a domain name, there should be no expectation this domain name represents a tangible entity or offers meaningful recourse. There are thousands of entities involved in these associations, where the basis is often limited to just the domain name itself. It is difficult to consider an amalgam of often anonymous entities a "trusted third party" for "securing" email interactions. Use of DNS by DKIM certainly falls short of the expectations of a TTP as set by Certificate Authorities or the example given of a notary public. For DKIM to offer security, a separate assessment of the DKIM domain name should be made (likely by a TTP). In that sense of trust or "securing" interactions, DNS fails this definition of TTP for email in my view.

-Doug

_______________________________________________
NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html

<Prev in Thread] Current Thread [Next in Thread>